Devices and systems having AC LED circuits and methods of driving the same

Abstract

A lighting device and system having at least one circuit, the circuit having at least two LEDs connected in series, parallel or anti-parallel configuration and at least one current limiting diode. The device or system may be driven with AC or DC power and may further include a sensor and polarity switching circuit to utilize all LEDs within the circuit when drive by DC power.

What is claimed is: 
     
       1. A method of driving a lighting device or system, the method comprising the steps of:
 connecting at least two LEDs such that at least one of the at least two LEDs is capable of emitting light during a positive phase from an AC power source, and at least one of the at least two LEDs is capable of emitting light during a negative phase from an AC power source; 
 providing DC power across the at least two LEDs, the at least two LEDs forming a load such that at least one of the at least two LEDs is forward biased by the DC power and at least one of the at least two LEDs is reversed biased by the DC power; 
 sensing the load to insure that the at least one LED configured to be forward biased by the DC power is operational; and, 
 reversing the polarity of the DC power across the load dynamically so as to forward bias the at least one LED that was previously reverse biased if the at least one LED previously configured to forward biased is no longer operational. 
 
     
     
       2. The method of  claim 1  further comprising the steps of sensing the load at a DC power supply to insure that the at least one LED configured to be forward biased by the DC power is operational; and,
 reversing the polarity of the DC power across the load dynamically at the DC power supply so as to forward bias the at least one LED that was previously reverse biased if the at least one LED previously configured to forward biased is no longer operational. 
 
     
     
       3. The method of  claim 1  further comprising the step of: providing a switch for reversing the polarity of the DC power across the load manually using the switch so as to forward bias the at least one LED that was previously reverse biased. 
     
     
       4. The method of  claim 1  further comprising the step of: reversing the polarity of the DC power across the load by manually disconnecting the circuit from the DC power and reconnecting the circuit to the DC power in a reversed configuration so that the at least one LED that was previously reverse biased is now forward biased. 
     
     
       5. The method  claim 1  further comprising the step of connecting the at least two LEDs in an anti-parallel configuration. 
     
     
       6. The method of  claim 5  further comprising the step of connecting at least one current limiting diode in series with each of the at least two LEDs. 
     
     
       7. The method of  claim 1  further comprising the step of connecting at least four diodes in a bridge configuration, wherein at least two of the at least four diodes are LEDs and at least two of the at least four LEDs are forward biased when connected to DC power, and at least two of the at least two LEDs are reversed biased when connected to DC power. 
     
     
       8. The method of  claim 7  further comprising the step of connecting at least one constant current diode across the output of the bridge rectifier. 
     
     
       9. The method of  claim 7  further comprising the step of connecting at least one wire across the output of the bridge rectifier.